JP2000104656A - Radial plunger pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To shorten the size in the axial direction by deleting the flange of a plug sealing the releasing end of a cylinder. SOLUTION: The plural number of cylinders 2 are formed almost in the radial direction in a pump housing 1 so as to be disposed roughly at equal intervals in the circumferential direction. Each plunger 5 is mounted to the insides of the plural cylinders 2 so as to be freely slidable, and a pump chamber 7 is formed in the inside of each cylinder 2 the volume of which is expanded/ contracted by the slide movement of each plunger 5. A rotating shaft 10 provided with an eccentric cam 11 driving each plunger 5 is provided to the side to which the axial line of each plunger 5 is converged. A cover member 30 provided with each slice 33 is mounted to one side surface of the pump housing 1 which is in contact with each plug 3, and prevents each plug 3 from slipping out in the positioning direction and the radial direction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radial plunger pump suitable for use as a power source for various hydraulic devices such as automobiles.

[0002]

2. Description of the Related Art As a radial plunger pump of this type, the present applicant has proposed an improved technique disclosed in Japanese Patent Application Laid-Open No. Hei 10-18960.

[0003] The radial plunger pump described in the above publication is provided with a plurality of cylinders which are formed on a pump housing in a radial direction so as to be open to the outer periphery of the pump housing and are arranged at substantially equal intervals in a circumferential direction. A plug that is inserted into each open end of the plurality of cylinders and seals the open end of the cylinder, and is slidably mounted in each of the plurality of cylinders whose open ends are sealed by the plug;
The cylinder includes a plunger forming a pump chamber in the cylinder, and a rotating shaft provided on a side where the axis of the plunger converges and having an eccentric cam for driving the plunger.

A plug for sealing the open end of the cylinder is screwed and fixed to the open end of the cylinder, and has a radial flange for restricting the amount of screwing of the plug and positioning in the radial direction. I have.

That is, when the plug is screwed into the open end of the cylinder, the amount of screwing is restricted by the flange of the plug being in contact with the open end surface of the cylinder, and the plug is positioned in the radial direction.

[0006]

By the way, the radial plunger pump can be widely used as a power source for various hydraulic devices, but depending on the form of use, the axial dimension of the pump (the axial dimension of the rotary shaft) is reduced. Is required. In particular, when the radial plunger pump is disposed on the side of the hydraulic device and the pump housing of the radial plunger pump and the housing of the hydraulic device are integrally formed, a flange formed on the plug that seals the open end of the cylinder However, it is necessary to reduce the axial dimension of the radial plunger pump by eliminating the flange of the plug since there is a risk of interference with the housing of the hydraulic device.

The present invention has been devised in view of the above-mentioned conventional circumstances, and eliminates the plug flange for sealing the open end of the cylinder to reduce the axial dimension of the radial plunger. It is intended to provide a pump.

[0008]

Therefore, according to the present invention, a plurality of pump housings are formed on the pump housing so as to be opened to the outer peripheral side of the pump housing in a substantially radial direction, and are formed at substantially equal intervals in a circumferential direction. A plunger that is slidably mounted in each of the arranged cylinders and a plurality of cylinders whose open ends are sealed by the plugs, and a plunger that forms a pump chamber in the cylinder, and a plunger on the side where the axis of the plunger converges A rotary shaft provided with an eccentric cam for driving the plunger; and a tongue attached to one side of the pump housing to contact the plug and prevent the plug from positioning and being radially pulled out. And a cover member.

According to a second aspect of the present invention, in the configuration of the first aspect, the tongue of the cover member has a suitable elasticity in a direction in which the plug is removed.

According to a third aspect of the present invention, in the configuration of the first aspect, a notch is formed in the tongue of the cover member to face the plug and to be released in the axial direction of the rotating shaft. It has a configuration that has been done.

The invention according to a fourth aspect of the present invention is the configuration according to the first aspect of the invention, wherein the tongue of the cover member is in contact with the plug via a spring member.

According to such a configuration, when the rotary shaft is driven to rotate, the eccentric cam provided on the rotary drive shaft drives the plunger, and the plunger moves in the cylinder in accordance with the lift amount of the eccentric cam. It reciprocates in the axial direction to expand and contract the pump chamber. By expanding and contracting the pump chamber,
The working liquid is sucked into the pump chamber, pressurized in the pump chamber, discharged from the pump chamber, and guided to the discharge port.

The plug for sealing the open end of the cylinder is inserted into the open end of the cylinder, is positioned by the tongue of the cover member in contact with the plug, and is prevented from being pulled out in the radial direction. I have.

Therefore, the outer diameter of the plug is substantially equal to the inner diameter of the cylinder, and the plug has no flange or the like for positioning. Therefore, the axial dimension of the radial plunger pump can be reduced accordingly.

Accordingly, a radial plunger pump can be obtained in which the axial dimension can be shortened by eliminating the plug flange for sealing the open end of the cylinder.

According to the second aspect of the present invention, the tongue of the cover member has an appropriate elasticity in the direction in which the plug is pulled out, so that the elasticity of the tongue acts on the plug. Fluctuations in hydraulic pressure in the pump chamber can be reduced.

According to the third aspect of the present invention, the tongue of the cover member is formed with a notch that faces the plug and is released in the axial direction of the rotating shaft. The notch prevents the tongue from interfering with the tool in a state where the cover is inserted into the cylinder with a shaft-shaped tool from the outside in the direction, so that the cover member can be easily assembled in the axial direction.

Further, in the invention according to claim 4, the tongue of the cover member is in contact with the plug via the spring member, and the elasticity of the spring member allows the elasticity of the spring member to act on the plug. Fluid pressure fluctuation can be reduced.

[0019]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a sectional view of a radial plunger pump showing an embodiment of the present invention, FIG. 2 is a sectional view taken along line AA of FIG. 1, and FIG. 3 is a view taken in the direction of arrow B in FIG.

In FIG. 1, reference numeral 1 denotes a pump housing.
The pump housing 1 is formed integrally with a housing of a hydraulic device (not shown), and the hydraulic device is disposed on the right side in FIG.

A plurality of (four in this embodiment) cylinders 2 are formed in the pump housing 1 substantially in the radial direction, and these cylinders 2 are arranged at substantially equal intervals in the circumferential direction. Each of the cylinders 2 is formed so as to be open to the outer peripheral side of the housing 1, and a plug 3 is inserted into the open end of the cylinder 2 and sealed by the plug 3. A side on which the axes of the plurality of cylinders 2 converge;
That is, an annular recess 4 is formed on the side opposite to the open end sealed by the plug 3, and each cylinder 2 communicates with the inside of the annular recess 4.

A plunger 5 is slidably mounted in each of the plurality of cylinders 2. The plunger 5 is attached via a cylindrical sleeve 6 integrally formed with the plug 3 in this embodiment. The plunger 5 has a cylindrical shape with a bottom, and the bottom 5 a is arranged so as to face the annular concave portion 4. A pump chamber 7 whose volume expands and contracts is formed. The plunger 5 has a body portion 5b formed with a suction hole 8 formed therethrough, and is urged radially inward by a spring 9 having one end in contact with the plug 3.

A rotary shaft 10 is provided on the side where the axis of the plunger 5 converges. The rotary shaft 10 is accommodated in the annular recess 4 and supported by the pump housing 1. An eccentric cam 11 for driving the plunger 5 is formed on the rotating shaft 10. The eccentric cam 11 is in contact with the bottom 5a of the plunger 5 via the bearing 12, and moves the plunger 5 in the radial direction by the rotation of the rotating shaft 10.

Reference numeral 13 denotes a pressure chamber which is attached to the pump chamber 7 in the cylinder 2 and through which the liquid pressurized from the pump chamber 7 is guided. The pressure chamber 13 is formed between the adjacent cylinders 2, and in this embodiment, the adjacent cylinders 2 are connected to each other to form an annular shape as a whole. The pressure chamber 13 is formed in the pump housing 1 by casting when the pump housing 1 is cast.
It is formed together with the rough shape of the cylinder 2. Although the inner periphery of the pressure chamber 13 is used as cast, the inner periphery of the roughly cast cylinder 2 is subjected to predetermined machining.

The plug 3 has a circumferential groove 16 communicating with the pressure chamber 13 through the cylinder 2, a diametrical through hole 17 opening at the bottom of the circumferential groove 16, and a pump communicating with the through hole 17. An axial stepped blind hole 18 opening into the chamber 7 is formed. In the blind hole 18, there is provided a check valve 22 that is adapted to a valve hole 21 a of a hollow plug 21 in which the valve element 19 is biased by a check spring 20 and fixed to the open end of the blind hole 18. Valve 22
When the valve body 19 opens the valve hole 21 a of the hollow plug 21, the working liquid pressurized in the pump chamber 7 is supplied to the hollow plug 21.
Through the valve hole 21a, the through hole 17 and the circumferential groove 16 into the pressure chamber 13.

Reference numeral 23 denotes a suction port formed in the housing 1 and communicating with a liquid storage tank (not shown). The suction port 23 is formed in the axial direction of the rotating shaft 10 and has an annular recess 4.
The inside of the annular recess 4 forms a suction chamber 24 for the working liquid. Therefore, as shown in FIGS. 1 and 2, the eccentric cam 11 of the rotary shaft 10 is disposed in the suction chamber 24, and the bottom 5a of the plunger 5 faces.

Reference numeral 25 denotes a discharge port formed in the pump housing 1. The discharge port 25 is connected to the pressure chamber 13.
And is formed in the axial direction of the rotary shaft 10 to guide the working liquid discharged into the pressure chamber 13 to an actuator (not shown).

Reference numeral 30 denotes a cover member attached to one side surface of the pump housing 1. The cover member 30 is a side surface opposite to the side surface on which the hydraulic equipment is disposed (in this embodiment, the left side surface in FIG. 1). ).

The cover member 30 includes a flat plate portion 31 in contact with one side surface of the pump housing 1 and a flat plate portion 31.
And a tongue 33 extending in the axial direction and formed on the outer periphery of the flat plate portion 31. Although the tongue piece 33 is formed continuously in a ring shape in this embodiment, the present invention is not limited to this, and it may be configured to be formed only at a position facing the plug 3.

The cover member 30 has a flat plate portion 31 attached to one side surface of the pump housing 30 by bolts 34 so as to be integral with the pump housing 1. The rotary shaft 1 is provided via a bearing 35 disposed on the inner periphery of the cylindrical portion 32.
0 is rotatably supported.

The tongue piece 33 formed on the cover member 30
Is in contact with the plug 3 to prevent the positioning of the plug 3 and the removal in the radial direction. The thickness of the tongue piece 33 of the cover member 30 is smaller than that of the flat plate portion 31.
As a result, the tongue piece 33 is given an appropriate elasticity in the direction in which the plug 3 is removed. The magnitude of the spring force of the tongue piece 33 is preferably selected so as to oppose the discharge pressure in the normal use area. The tongue piece 33 is formed with a notch 36 which faces the plug 3 and is released in the axial direction of the rotating shaft 10.

The pump housing 1 of the cover member 30
Attachment is performed as follows. That is, first, the plug 3 is inserted into the open end of the cylinder 2, and then the plug 3 which is to be protruded in the radial direction by the spring 9.
Is pressed by a shaft-like tool (not shown) from the outside in the radial direction, and is kept inserted in the cylinder 2. In this state,
The cover member 30 is assembled in the axial direction and attached with bolts 34. At this time, the notch 36 formed in the tongue piece 33 prevents interference between the tongue piece and the tool, and the cover member 3
0 is easily assembled in the axial direction. Thereafter, the tool pressing the plug 3 is removed. Thus, the attachment of the cover member 30 to the pump housing 1 is completed.

Reference numeral 38 denotes a seal ring provided on the body of the plug 3, and reference numeral 39 denotes a seal ring provided on the body of the sleeve 6. Reference numeral 40 denotes a seal member provided on the cylindrical portion 32 of the cover member 30.
The space between the cylindrical portion 32 of the cover member 30 integrated with the pump housing 1 and the rotating shaft 10 is sealed.

According to such a configuration, the rotary shaft 10 is rotationally driven by an internal combustion engine or the like via a pulley (not shown), whereby the eccentric cam 11 formed on the rotary shaft 10 rotates. As a result, the plunger 5 urged by the spring 9 and whose bottom portion 5a is in contact with the eccentric cam 11 via the bearing 12 reciprocates in the cylinder 2 in the axial direction according to the lift amount of the eccentric cam 11, Pump room 7
Scales.

The plunger 5 comes into contact with the reference circle of the eccentric cam 11 and protrudes most into the suction chamber 24. The suction hole 8 formed in the body 5 b of the plunger 5 opens into the suction chamber 24, so that the suction is performed. The working liquid in the chamber 24 is sucked through the suction hole 8 into the pump chamber 7 having an increased volume.

When the lift of the eccentric cam 11 increases, the plunger 5 moves, the suction hole 8 is closed by the cylinder (in this embodiment, by the sleeve 6), and the pump chamber 7 and the suction chamber 24 are closed. Communication with is interrupted. As a result, the working liquid sucked into the pump chamber 7 is pressurized most in the pump chamber 7 where the plunger 5 has the smallest volume at the maximum lift position of the eccentric cam 11, and the check valve 22 is opened to increase the pressure. It is discharged into the chamber 13. That is, the pressure in the pump chamber 7 causes the valve body 19 of the check valve 22 to move against the spring force of the check spring 20 to open the valve hole 21a of the hollow plug 21 and to be pressurized in the pump chamber 7. The working liquid is discharged into the pressure chamber 13 through the valve hole 21a, the blind hole 18, the through hole 17, and the circumferential groove 16.

The working liquid discharged into the pressure chamber 13 is supplied to an actuator (not shown) from a discharge port 25 which opens substantially in the same direction as the rotating shaft 10.

Here, the plug 3 for sealing the open end of the cylinder 2 is inserted into the open end of the cylinder 2 and is positioned by the tongue piece 33 of the cover member 30 in contact with the plug 3 and in the radial direction. Pull-out is prevented.

For this reason, the plug 3 is formed so that its outer diameter is substantially equal to the inner diameter of the cylinder 2 and has no flange or the like for positioning. Therefore, the axial dimension of the radial plunger pump is reduced accordingly. it can.

Accordingly, a radial plunger pump can be obtained in which the flange of the plug 3 for sealing the open end of the cylinder 2 is omitted, and the axial dimension can be reduced.

Further, since the plug 3 is inserted into the cylinder 2 to seal the open end thereof, there is no need to form a screw in the plug 3 to perform a screwing operation, thereby facilitating processing and assembly.

The tongue piece 33 of the cover member 30 is
Since the plug 3 has an appropriate elasticity in the pulling-out direction, the elasticity (spring force) of the tongue piece 33 can reduce the hydraulic pressure fluctuation in the pump chamber 7 acting on the plug 3.
In particular, by setting the spring force of the tongue piece 33 to a level that opposes the discharge pressure in the normal range, a surge pressure equal to or higher than the normal pressure can be effectively absorbed.

The tongue piece 33 of the cover member 30 is formed with a notch 36 which faces the plug 3 and is released in the axial direction of the rotary shaft 10. With the tool inserted in the cylinder 2
The notch 36 prevents interference between the tongue piece 33 and the tool, so that the cover member 30 can be easily assembled in the axial direction.

FIG. 4 is a view showing another embodiment of the present invention. This embodiment is different from the embodiment described above in that the tongue piece 33 of the cover member 30 is connected to a plug via a spring member 41. 3.

That is, a spring member 41 is disposed between the plug 3 and the tongue piece 33 of the cover member 30. Thereby, the tongue piece 33 of the cover member 30 is
Through the plug 3. In this embodiment, a frusto-conical disc spring is used as the spring member 41, and the spring force of the spring member 41 is preferably selected to have a magnitude that antagonizes the discharge pressure in a normal range.

The other components are the same as those of the above-described embodiment. Therefore, the same components are denoted by the same reference numerals, and redundant description will be omitted.

In this structure, the plug 3 for sealing the open end of the cylinder 2 is inserted into the open end of the cylinder 2 and is positioned by the tongue piece 33 which is in contact with the plug 3 via the spring member 41. At the same time, withdrawal in the radial direction is prevented.

Therefore, the outer diameter of the plug 3 is formed to be substantially equal to the inner diameter of the cylinder 2 and has no flange or the like for positioning. Therefore, the axial dimension of the radial plunger pump can be shortened accordingly. it can.

Therefore, even in this embodiment, a radial plunger pump capable of shortening the axial dimension by eliminating the flange of the plug 3 for sealing the open end of the cylinder 2 is provided. can get.

In addition, the tongue piece 33 of the cover member 30
Is in contact with the plug 3 via the spring member 41,
Due to the elasticity of the spring member 41, fluctuations in hydraulic pressure in the pump chamber 7 acting on the plug 3 can be reduced. In particular, by setting the spring force of the spring member 41 to a magnitude that opposes the discharge pressure in the normal range, a surge pressure equal to or higher than the normal pressure can be effectively absorbed.

Although the embodiment has been described with reference to the drawings, the specific configuration is not limited to this embodiment and can be changed without departing from the spirit of the invention.
For example, although the embodiment in which the plunger 5 is disposed in the cylinder 2 via the sleeve 6 has been described, a configuration in which the plunger 5 is disposed directly in the cylinder 2 may be adopted. The volume can be increased.

[0053]

As described above in detail, according to the present invention, the radial plunger capable of shortening the axial dimension by eliminating the plug flange for sealing the open end of the cylinder. A pump is obtained.

[Brief description of the drawings]

FIG. 1 is a sectional view of a radial plunger pump showing an embodiment of the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a view in the direction of arrow B in FIG. 1;

FIG. 4 is an enlarged sectional view of a main part of a radial plunger pump showing another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Pump housing 2 Cylinder 3 Plug 5 Plunger 7 Pump room 10 Rotating shaft 11 Eccentric cam 30 Cover member 33 Tongue

Claims (4)

[Claims] 1. A plurality of pump housings are formed in a radial direction so as to be open to the outer peripheral side of the pump housing.
Cylinders arranged at substantially equal intervals in the circumferential direction, plugs inserted into the respective open ends of the plurality of cylinders, and sealing the open ends of the cylinders, and a plurality of the open ends sealed by the plugs A plunger that is slidably mounted in each of the cylinders and forms a pump chamber in the cylinder, and a rotating shaft that is provided on a side where the axis of the plunger converges and has an eccentric cam that drives the plunger;
A radial plunger pump, comprising: a cover member attached to one side surface of the pump housing and having a tongue piece for contacting the plug and preventing positioning of the plug and radial removal thereof. . 2. The radial plunger pump according to claim 1, wherein the tongue piece of the cover member has appropriate elasticity in a direction in which the plug is removed. 3. The radial plunger pump according to claim 1, wherein a notch is formed in the tongue of the cover member so as to face the plug and to be released in the axial direction of the rotation shaft. 4. The radial plunger pump according to claim 1, wherein the tongue of the bagger member contacts the plug via a spring member.